A new drug for Alzheimer’s called Leqembi® (generic name lecanemab) made history in January 2023 following a rare move by the Food and Drug Administration (FDA) to accelerate its approval. Months later, Leqembi made history again. That’s when the FDA granted traditional approval for it—the first time it’s ever done so for a drug of its type.

Next to Aduhelm™, Leqembi was only the second anti-amyloid Alzheimer’s disease treatment on the market.1 It was also the first to qualify for broader coverage under original Medicare.2

“This was a milestone announcement and encouraging news for millions of adults with early-stage dementia who might benefit from Leqembi, but otherwise may struggle to access or pay for it,” said Kathleen Cameron, senior director of NCOA’s Center for Healthy Aging. “Traditional FDA approval removes some of those barriers, but it’s important for patients and caregivers to talk to their doctor to fully understand its potential benefits and risks.”

Get answers to commonly asked questions about this Alzheimer's treatment below.

What does the drug Leqembi do?

Leqembi is a biologic drug designed to slow Alzheimer’s progression by identifying and attacking beta amyloid proteins in the brain—what experts consider to be hallmarks of the disease. Beta amyloid proteins clump together to form plaques that destroy neurons, which are the cells that form the brain’s communication system.3 Leqembi binds to these plaques and breaks them apart.4

“Other available medications for Alzheimer’s only treat its symptoms,” Cameron explained. “Leqembi is designed to slow the disease process itself, and early testing suggested that it worked.”

What are the side effects of Leqembi?

Leqembi's long-term safety remains to be seen, Cameron cautioned. The drug’s potential side effects are serious enough that the FDA requires a boxed warning on its packaging.5

Leqembi’s most common side effects include:

  • Headache
  • Infusion-related reactions
  • Temporary brain swelling
  • Small brain bleeds

Together, those last two bullet points describe a phenomenon called amyloid-related imaging abnormalities, or ARIA. Most often, ARIA causes no symptoms and usually resolves over time. Some patients with ARIA will experience nausea, dizziness, confusion, or vision changes. Rarely, ARIA can cause life-threatening brain swelling and fatal brain hemorrhage. 

Certain patients are at higher risk for ARIA, including:5

  • Those with the APOE4 gene mutation (a mutation correlated with Alzheimer’s)
  • Those who use blood thinners
  • Those with previous histories of microscopic brain bleeds

Patients should work closely with their health care team to fully understand their individual risks and weigh them against the potential benefits of Leqembi before deciding to try it.

Does Leqembi really work?

It depends. It’s important to know that Leqembi does not cure Alzheimer’s or reverse the changes that have already occurred due to the diseasep. But it can slow cognitive decline in patients with early-stage disease.

Results from Leqembi’s confirmatory study, which enrolled 1,795 patients with Alzheimer’s in a multi-center clinical trial, showed a “statistically significant” and “clinically meaningful” reduction in that decline over a period of 18 months for participants who received Leqembi versus those who received a placebo.5

That said, the way researchers measured and quantified their results necessarily were subjective, Cameron explained. That’s because they relied on participants to rate their own perceived changes during the course of the study. Using a five-point scale, participants described their performance in areas such as memory, problem-solving, and personal care at the beginning and end of the study. Researchers calculated the differences and concluded that those who received Leqembi experienced a 27% slower rate of cognitive decline than those who hadn't.5

This is currently the best way for clinical investigators to evaluate Leqembi’s outcomes, Cameron said, and those outcomes are encouraging. Yet they leave an important question open.

“No one can say for certain how well Leqembi really works without objective data to back it up—and that will take time,” she said. “And we don’t know how effective it will be for any specific individual. Just because one patient responds well to treatment doesn’t mean that another will.”

Still, Leqembi may help some patients maintain their independence and ability to participate in daily life for longer. For many people with early-stage Alzheimer’s, that’s enough. Beyond those 18 months, Leqembi’s impact on Alzheimer's progression remains unknown.

Who can get Leqembi?

In theory, anyone diagnosed with early-stage Alzheimer’s disease who qualifies under FDA rules can get Leqembi. Currently, the drug is not approved for treating more advanced stages of the disease or for patients who do not show any symptoms.

Leqembi’s prescribing information requires that patients undergo diagnostic testing to confirm the presence of beta amyloids before they can begin treatment.6 Generally, doctors accomplish this with a PET scan or by examining cerebrospinal fluid obtained through a lumbar puncture (spinal tap).

Still, equitable access remains “a large elephant in the room,” Cameron pointed out. “In addition to its high price tag—which puts Leqembi out of reach for many older adults even if they have Medicare coverage—traditionally marginalized communities face additional barriers to getting this treatment,” she said.

Already, the Kaiser Family Foundation has raised questions over whether the treatment aggravates racial disparities in elder care. While the issues are complex, said Cameron, policymakers must work together to unravel and address them.

According to the Kaiser Family Foundation article, known issues include:

1. Underrepresentation in clinical trials
Leqembi’s confirmatory study failed to include a diverse cohort of participants. Taken at face value, the reason is sound: because Black patients with Alzheimer’s don’t show elevated beta amyloid proteins as early as white patients do, they automatically were excluded from testing. However, as Cameron pointed out, that uncovers trickier questions that deserve answers.

“If one racial or ethnic group exhibits the same cognitive changes as another, but their levels of beta-amyloid aren’t yet elevated, don’t they still deserve the same access to potentially life-altering treatment? Beyond that, should elevated beta-amyloid be the sole factor taken into consideration when diagnosing the disease?”

2. Delayed diagnosis
Marginalized people—those with lower incomes, for example, or limited English-language skills—do not have the same access to diagnostic testing as those who are more privileged. Because Leqembi is only approved for use in early-stage Alzheimer’s disease, many patients who might otherwise benefit from the drug will miss out under current guidelines. They simply will be diagnosed too late.

“That said, it’s worthwhile to note, once again, that we don’t know how safe and effective this drug truly is,” Cameron said, referring to another point made in the article: that other concurrent, underlying health issues may contribute to cognitive decline in certain populations who weren’t originally included in clinical trials.

“It’s possible that Leqembi would not be a good treatment choice in those situations, she said. “That’s precisely why we need more robust studies that take these factors into account.”

How is Leqembi given and for how long?

Leqembi is not available in a pill form and is not taken by mouth. This medication is given intravenously (through a vein) by infusion over a one-hour period every two weeks for an indefinite period of time. Patients prescribed this medication must go to an infusion clinic or other medical setting to receive the medication by infusion.

This requirement raises further equity concerns for people who do not live near infusion centers or medical settings equipped to administer the medication and for those who don’t have reliable access to transportation to get to the centers.

Yet a more convenient way of administering Leqembi may soon be on the way—since an injectable version of the drug showed promising initial results in a clinical trial. A subcutaneous injection would allow patients to administer this Alzheimer's treatment at home, eliminating the need to travel to a hospital or other infusion center every two weeks.

Will Medicare cover Leqembi?

Since it was approved by the FDA, Medicare “broadly covers” Leqembi. However, certain conditions must be met first. Prescribing physicians must agree to enter patient information into a federal registry.7 The Centers for Medicare and Medicaid (CMS) hope this requirement encourages additional real-world data that ultimately will help the scientific community better understand how the drug works.

According to CMS, Medicare will cover Leqembi only for patients already enrolled in Medicare and who meet the FDA rules outlined under “Who can get Leqembi?” above.

How much does Leqembi cost?

Eiasi, Leqembi’s manufacturer, set the drug’s list price at $26,500 per year.8 “That’s still a lot of money,” said Cameron.

“Also keep in mind that Medicare beneficiaries will still be responsible for their out-of-pocket costs,” Cameron advised. That means patients will pay 20% of Leqembi’s cost after meeting their Part B deductible. It's something patients and caregivers need to consider before starting treatment."

Specifically, the out-of-pocket cost for Medicare enrollees will be $5,300 per year. For those with Medicare supplemental or other secondary insurance, the costs may be less. For someone enrolled in a Medicare Advantage plan, the out-of-pocket cost will vary, but could be as much as 20%.

As for Medicaid: it might cover Leqembi in some cases—without requiring the prescribing doctor to enter patient data into a federal registry. But it depends on where patients live and other factors. The best way to find out if Medicaid covers this Alzheimer’s treatment is to contact your state Medicaid office.

What about donanemab?

Another Alzheimer’s medication that targets amyloid proteins in the brain, donanemab, has shown promise in slowing functional and cognitive decline for people in early stages of the disease.9 The drug's manufacturer, Eli Lilly, has applied to the FDA for traditional approval of the drug. That approval could come sometime in 2024.

Phase 3 clinical trial results, which were reported in July 2023, showed that donanemab markedly slowed cognitive and functional decline in people with early symptomatic Alzheimer's disease. Nearly half (47%) of participants in the earliest stages of Alzheimer's who received donanemab had no clinical progression of the disease at one year.10

While clinical trial results are encouraging, donanemab carries the same safety concerns as lecanemab. Patients who take either drug must be monitored closely for brain swelling and bleeding. And neither drug has been tested long-term.

For more information on the latest treatments for Alzheimer’s, be sure to visit and bookmark NCOA’s Alzheimer's / Dementia for Older Adults  resource page


1. Alzheimer’s Association. Treatments and Research. Found on the internet at https://www.alz.org/help-support/i-have-alz/treatments-research

2. BioSpace. CMS Expands Medicare Coverage for Leqembi After FDA Traditional Approval. Found on the internet at https://www.biospace.com/article/cms-expands-medicare-coverage-for-leqembi-after-fda-traditional-approval/

3. National Institute on Aging. What Happens to the Brain in Alzheimer’s Disease? Found on the internet at https://www.nia.nih.gov/health/what-happens-brain-alzheimers-disease

4. Jeffrey Cummings, et. al. Alzheimer’s disease drug development pipeline: 2022. Translational Research and Clinical Interventions, May 4, 2022. Found on the internet at https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/trc2.12295vestor.lilly.com/news-releases/news-release-details/results-lillys-landmark-phase-3-trial-donanemab-presented

5. Adam Feuerstein, et. al. FDA approves first Alzheimer’s therapy shown to clearly slow cognitive decline. STAT. July 6, 2023. Found on the internet at https://www.statnews.com/2023/07/06/leqembi-alzheimers-fda-approval-eisai-biogen/

6. Alzheimer’s Association. Lecanemab approved for treatment of early Alzheimer’s Disease. Found on the internet at https://www.alz.org/alzheimers-dementia/treatments/lecanemab-leqembi

7. Centers for Medicare & Medicaid Services. Statement: Broader Medicare Coverage of Leqembi Available Following FDA Traditional Approval. Found on the internet at https://www.cms.gov/newsroom/press-releases/statement-broader-medicare-coverage-leqembi-available-following-fda-traditional-approval

8. PR Newswire. Eisa's approach to U.S. pricing for Leqembi (lecanemab), a treatment for early Alzheimer's...Jan. 6, 2023. Found on the internet at https://www.eisai.com/news/2023/news202302.html

9. John R. Sims, et al. Donanemab in Early Symptomatic Alzheimer Disease: The TRAILBLAZER-ALZ 2 Randomized Clinical Trial. JAMA. July 27, 2023. Found on the internet at https://jamanetwork.com/journals/jama/fullarticle/2807533

10. Lilly Investors. Results from Lilly's Landmark Phase 3 Trial of Donanemab Presented at Alzheimer's Association Conference and Published in JAMA. July 17, 2023. Found on the internet at https://investor.lilly.com/news-releases/news-release-details/results-lillys-landmark-phase-3-trial-donanemab-presented